What is epilepsy? Diagnosis, Treatment and Surgery
Epilepsy continues to evoke emotions of fear. Misunderstandings regarding its treatment still exist in the community. For those unfortunates within whom medical treatment fails to control seizures adequately, surgical management is a definitive treatment option.
Epilepsy surgery has been scientifically proven to be effective and safe in seizure control and in improving quality of life in appropriately selected patients. With advances in science, treatment options are available that can help a person with epilepsy lead an essentially normal life.
What is epilepsy?
Epileptic ‘seizures’ or ‘fits’ in common parlance, refers to the short lasting signs or symptoms that occur due to abnormal and excessive misfiring of brain cells. It can be characterized by brief episodes of involuntary movements that may involve a part of or the entire body, and can be accompanied by loss of consciousness and control of bowel or bladder function. The term epilepsy has a different connotation, pointing to an ongoing predisposition for repeated seizures and also to the ensuing physical, psychological and social consequences of this condition.
Epilepsy: The problem
Latest WHO numbers reveal that about 50 million people are living with epilepsy worldwide with nearly 2.5 million new cases being diagnosed each year. It is a major public health problem and uncontrolled epilepsy can have serious consequences with neurological, psychological and social disabilities that adversely affect the quality of life of the person and their families and even can cause unexpected sudden deaths.
Treatment of epilepsy
The treatment of epilepsy would require the correct diagnosis of the nature and type of epilepsy by an expert doctor. This would include a detailed account from the patient and family members, supported by necessary investigations such as EEG and MRI in selected cases. With correct treatment, about 70% patients will have seizure freedom or significant reduction in disability. The type and number of medicines, its dose and duration of treatment would vary from person to person and is best clarified with the treating doctor. There are many misconceptions regarding antiepileptic medicines and the most common reason for poor seizure control is poor drug compliance. It is best to openly discuss with the doctor all your concerns and also to report back in case of any perceived side effects.
Surgical management of epilepsy
The definition of drug resistant epilepsy is lack of response despite adequate trials of two appropriate antiepileptic drugs but is not rigid and depends on patient variables. Despite instituting the correct medicines in their appropriate dose, around 30% of patients would continue to have disabling and debilitating seizures.
These patients who continue to exhibit uncontrolled seizures despite maximally tolerated doses of medicines are considered to have medically refractory epilepsy. This group of patients who are unlikely to have significant seizure freedom with drugs could be viable candidates for epilepsy surgery. Studies have shown that appropriate and early epilepsy surgeries can significantly increase chances of total seizure freedom, reduce epilepsy related neuropsychological complications and lead to better quality of life.
Principle of epilepsy surgery
The principle of epilepsy surgery is to find and remove or disconnect the focus of abnormality in the brain. This could lead to considerable reduction in seizure frequency or a complete seizure freedom. Bearing in mind the fact that the brain is the most complex structure in the universe and that each part of brain has its own vital function, utmost care has to be taken in minimising the extent of removal or disconnection, to limit the functional disability.
It consists of a multidisciplinary approach with the team (comprehensive epilepsy team) consisting of epileptologist, epilepsy surgeon, neuroradiologist, neuropsychologist, speech and language therapist and occupational therapist with patient and family always being at the epicenter.
Steps in Presurgical evaluation
Presurgical evaluation refers to the series of individualised investigations which would include a detailed clinical history and examination, review of the CT/MRI carried out in specialised epilepsy protocol, video EEG monitoring and neuropsychological evaluation, all of which would guide the team in deciding the patient’s candidacy for epilepsy surgery.
At the end of the evaluation, a collective decision regarding surgery will be taken in a patient management conference attended by all the members of comprehensive epilepsy team. After weighing all the benefits and potential side effects, the decision shall be discussed with the patient and the family in exhaustive detail.
The surgical conditions could range from involvement of all four lobes of one hemisphere of the brain to a small lesion in one lobe. It is not essential to shave the whole head in all patients undergoing epilepsy surgery. The surgery is generally performed after removing a small piece of skull which is replaced at the end of the procedure. Minimally invasive (key hole) epilepsy surgery techniques are becoming popular.
The duration of epilepsy surgery usually varies from 3 to 5 hours. There are different types of surgeries namely hemispherotomies/ quadrantic disconnections/ multilobar resections/ amygdalohippocampectomies/ anterior temporal lobectomies/ callosotomies, vagal nerve stimulation, lesionectomies, radiosurgery and deep brain stimulation.
The surgical approach would depend on the individual patient and the type of epilepsy. This is done by epilepsy surgeons who are highly trained to deal with these complex surgeries. The aim of surgery is to facilitate a seizure cure without worsening the neurological condition of the patient.
Follow-up after surgery
After surgery the patient can be discharged usually within 5-7 days. A scalp EEG would be done before discharge to guide further drug treatment. A gradual tapering of medicines shall be initiated from first visit after surgery onwards taking in to account the individual patient characteristics. Periodic short and long term follow-up visits shall be charted for constant monitoring and to address any concern from the patient and family. During follow-up, the patient will be under the direct care of the epileptologist and the antiepileptic drugs will be gradually tapered with close monitoring and in many patients can be completely taken out successfully.
(Article Authored by Dr Biji Bahuleyan, MCh. Neurosurgery (Vellore) Epilepsy Surgeon, KIMS; Dr. Santhosh George Thomas, MCh. Neurosurgery (Vellore), Epilepsy Surgeon, KIMS; Dr. Deepak Menon, DM (Neurology), Epileptologist)